The present disclosure relates to compacting machines, and more particularly to an assembly for oscillating a compacting drum of a compacting machine.
Compacting machines are used in leveling paved or unpaved ground surfaces. A typical compacting machine includes an eccentric assembly, which is located inside a compacting drum of the compacting machine and generates vibrations or oscillations due to its eccentricity while being rotated by an electrical or hydraulic motor. Then, the vibrations or oscillations generated by the eccentric assembly are transferred to the compacting drum, thereby enhancing the compacting efficiency of the compacting machine.
An eccentric assembly for vibrating a compacting drum provides radial vibrations that periodically change the value of a normal contact force exerted to the ground by the compacting drum, whereas an eccentric assembly for oscillating the compacting drum does not provide radial vibrations but provide oscillations that change the torque that rotates the drum, and thus, periodically change a tangential contact force exerted to the ground by the drum. Due to the absence of vibrations in a normal direction, eccentric assemblies for oscillating can be used on constructions that are sensitive to normal vibrations such as bridges.
The eccentric assembly for oscillating has two eccentric shafts that are positioned at the same distance from a central shalt driven by a motor, and are rotated in the same direction synchronously driven by the central shaft. In most of currently available eccentric assemblies for oscillation, the two synchronously rotating eccentric shafts are driven via the central shaft by means of toothed belts.
FIG. 7 schematically shows the interior of a compacting drum including an eccentric assembly for oscillating the compacting drum according to the prior art.
Positioned at the center of the compacting drum 400 is an assembly 300 for oscillating a compacting machine. A central shaft 260 of the assembly is driven by a motor 270, such as a hydraulic or electric motor, via a driving shaft 280. The central shaft 260 is rotatably mounted to two section walls 320 and 330 fixed, e.g., welded to the compacting drum 400, with each end of the central shaft 260 supported by bearings 290. The driving shaft 280 is connected to the central shaft 260 and the motor 270 by means of articulated joints at both ends thereof to allow the compacting drum 400 to vibrate. Two eccentric shafts, a first eccentric shaft 410 and a second eccentric shaft 420, are also rotatably mounted to the two sections walls 320 and 330 with each ends of the eccentric shafts 410 and 420 supported by bearings 430. The two eccentric shafts 410 and 420 are disposed equidistantly from the central shaft 260 in parallel to the central shaft 260, and thus, the two eccentric shafts 410 and 420 and the central shaft 260 are generally in the same plane. A drive pulley 265 is mounted at both ends of the central shaft 260, respectively. A driven pulley 415 is mounted at one end of the first eccentric shaft 410, and a driven pulley 425 is mounted at an end of the second eccentric shaft 420, which is positioned farther away from the one end of the first eccentric shaft 410 where the driven pulley 415 is mounted. The drive pulley 265 and the driven pulleys 415 and 425 are connected to two toothed belts 500. Thus, the rotational energy of the central shaft 260 is transmitted to the two eccentric shafts 410 and 420 so that the two eccentric shafts 410 and 420 can synchronously rotate.
However, this constitution lacks in durability and requires frequent servicing of the machine. In other words, the toothed belts are wearable, resulting in a degradation in reliability and a reduction in lifetime. In addition, a replaced toothed belt is required to be discarded, and thus the conventional oscillation mechanism is not environment-friendly. Meanwhile, a conventional oscillation mechanism of using a gear mechanism exists instead of using the two toothed belts to transmit the rotational energy of the central shaft to the two eccentric shafts, but it is complicated in its structure and requires high cost. Further, such a conventional oscillation mechanism is totally different in structure from the conventional oscillation mechanism using the toothed belts as shown in FIG. 7, and thus it is impossible to simply improve the conventional oscillation mechanism as shown in FIG. 7 using the conventional oscillation mechanism of using a gear mechanism.
Therefore, there is a need for an eccentric assembly for oscillating a compacting drum of a compacting machine, which can provide greater reliability and much longer lifetime to allow less serviceability to be needed, can eliminate the necessity for wearable belts to make a design simple while offering a more environment-friendly solution, and can be easily implemented in the conventional compacting machine using the toothed belts.
According to one aspect of the present disclosure, there is provided an eccentric assembly for oscillating a compacting drum of a compacting machine. The eccentric assembly includes:
a central disk rotatably mounted to the compacting drum to have an axis disposed in juxtaposition with an axis of the compacting drum, and configured to be rotatably driven by a motor;
a pair of opposed eccentric shafts, each axis of which is disposed equidistantly from the center of the axis of the central disk, the eccentric shafts being rotatably mounted to the compacting drum such that the three axes of the central disk and the eccentric shafts are in the same plane; and
a yoke disposed between the central disk and the two eccentric shafts in such a manner a to be connected to the central disk and the two eccentric shafts, respectively, by means of three connecting members.
One end of each of the connecting members is rotatably coupled to different positions of the yoke, and the other end thereof is fixed to a corresponding one of the central disk and the two eccentric shafts such that the two eccentric shafts rotate synchronously by the rotation of the central disk.